The present invention relates to a transverse link, and to a method for producing a transverse link.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Axle components in the form of track rods, links, or twist beams transmit static and dynamic wheel forces to an axle subframe or to a motor vehicle body. These axle components are rotatably and/or pivotally coupled between wheel carriers and vehicle-side attachment points, with the coupling normally realized via rubber-metal bearings.
Wheel forces being transmitted have hereby peak zones of up to several thousand Newton. As a result, the wheel guide links have to withstand high and intense peak loads and constant vibratory stress. In addition, various influences during driving, for example uneven road surfaces or unbalances of one vehicle wheel, expose the wheel guide links to further substantial vibrations.
The demands on today's motor vehicles to comply with dynamic driving profiles render it important to use especially lightweight structures on the sides of the unsprung wheel masses. Moreover, automobile manufacturers always demand a reduction of the total vehicle weight so as to reduce fuel consumption and CO2 emission.
Conventional links are normally made as steel components in order to meet the need for low weight, high stiffness, long life, and easy producibility. For example, multipart suspension links produced from steel are normally composed of an upper shell and a lower shell for attachment of various bearing mounts, spring mounts and also shock absorber mounts. Such a link is typically assembled by using welding for connections. This requires a number of operating steps and cumbersome anti-corrosive measures to provide a durable and robust component (cf. EP 1 336 514 A2).
The application of welding is disadvantageous because of the change in the hardness of the microstructure and of the heat impact zone surrounding the weld sea. In particular when geometrically complex components are involved, realization of a clean welding outcome is oftentimes difficult to attain. Another drawback of a welded steel construction is the resultant susceptibility to corrode. While the weld seams may enhance stiffness as a result of the coupling of various components to form a link, the addition of welding filler has the adverse effect of increasing weight.
Links may further be produced cost-effectively through primary-forming, for example casting. This allows implementation of links of, for example, X-shaped configuration. Casting renders the realization of geometrically complex shapes possible that cannot be achieved when a welded steel construction is involved. For example, links can be cast as hollow aluminum structures. Hollow spaces are normally realized by using expendable cores, e.g. sand cores or the like. Links made through casting are, however, disadvantageous, especially in the form of hollow components, because of the high production tolerance. The support of cores enclosed in the castings requires in some circumstances to leave the outer side open so that the torsional stiffness of such components is adversely affected. Another drawback of castings involves the high porosity of the component. This reduces strength compared to structures that have been produced by a forming process. The strength of castings is oftentimes enhanced by applying a subsequent forging process. The application of such a forging process increases production costs of the component however.
It would therefore be desirable and advantageous to address prior art shortcomings and to produce an improved link of high strength while yet having little weight and favorable producibility.